Functional evidence for the inflammatory reflex in teleosts: A novel alpha7 nicotinic acetylcholine receptor modulates the macrophage response to dsRNA

Citation

Torrealba D, Balasch JC, Criado M, Tort L, MacKenzie S & Roher N (2018) Functional evidence for the inflammatory reflex in teleosts: A novel alpha7 nicotinic acetylcholine receptor modulates the macrophage response to dsRNA. Developmental and Comparative Immunology, 84, pp. 279-291. https://doi.org/10.1016/j.dci.2018.02.020

Abstract
The inflammatory reflex modulates the innate immune system, keeping in check the detrimental consequences of overstimulation. A key player controlling the inflammatory reflex is the alpha 7 acetylcholine receptor (α7nAChR). This receptor is one of the signalling molecules regulating cytokine expression in macrophages. In this study, we characterize a novel teleost α7nAChR. Protein sequence analysis shows a high degree of conservation with mammalian orthologs and trout α7nAChR has all the features and essential amino acids to form a fully functional receptor. We demonstrate that trout macrophages can bind α-bungarotoxin (α-BTX), a competitive antagonist for α7nAChRs. Moreover, nicotine stimulation produces a decrease in pro-inflammatory cytokine expression after stimulation with poly(I:C). These results suggest the presence of a functional α7nAChR in the macrophage plasma membrane. Further, in vivo injection of poly(I:C) induced an increase in serum ACh levels in rainbow trout. Our results manifest for the first time the functional conservation of the inflammatory reflex in teleosts.

Keywords
α7nAChR; Nicotine; Poly(I:C); Innate immunity; Evolution

Journal
Developmental and Comparative Immunology: Volume 84

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